Obama held a White House news conference Friday. Obama says he realizes relations between the two super powers have been difficult lately. He says progress was being made until Putin regained the Russian presidency. Now Obama says there have been "a number of emerging differences," including over Syria and human rights.

The White House this week cancelled a planned summit between Obama and Putin next month in Moscow. That's in part because Russia is refusing to return National Security Agency leaker Edward Snowden to the U.S. to face charges of leaking national security secrets.